c-myc and c-ets (1 and 2) genes are cellular homologues of the oncogenes carried by the avian myelocytomatosis virus MC29 and the avian acute leukemia virus E26, respectively. These genes are suspected to have some roles in the pathogenesis of certain types of human malignancy. Production of monoclonal antibodies against products of these genes was planned for application to the biological and biochemical characterization of these products. A monoclonal antibody against the human myc gene products has already been produced and described in last year's report. This year, two monoclonal antibodies have been generated against the human ets-2 gene product. These antibodies recognize a 56 Kd nuclear protein from various human cell lines, which was identified as a product to the human ets-2 gene. One monoclonal antibody recognize two other proteins of 60 Kd and 53 Kd. These two proteins appear to be antigenically related to the 56 Kd ets-2 protein. The monoclonal antibodies also react with the ets-2 proteins from mouse, chicken and sea urchin. Thus, it is likely that the antibodies detect epitopes that are highly conserved in evolution. This high degree of conservation implies the functional importance of the domain detected by the antibodies. These antibodies are being used as immunological probes in the screening of cDNA expression library for ets-2-specific clones.